//定义变量
$color1:#f66;

//定义mixins
@mixin container {
    width:1200px;
    background-color: green;
}

@mixin clearfix {
    &:after {
      content: "";
      display: table;
      clear: both;
    }
  }

  .div {
    width: 200px;
    @include clearfix;
    @include container;
  }